BAGHDAD - A group linked to al-Qaeda in Iraq claimed responsibility yesterday for double suicide truck bombings that killed nine U.S. paratroopers in the worst attack on American ground forces in Iraq in more than a year. It sent "two knights" for the attack, the group said.

The Islamic State of Iraq, an umbrella group of Sunni extremists that includes al-Qaeda in Iraq, said it was behind Monday's attack on a U.S. patrol base in Diyala province northeast of Baghdad - an area that has seen violence spike since American troops surged into the capital to halt violence there.

"The first knight exploded his truck on them and he was followed by his brother in the second truck, exploding it on what remains from the soldiers inside the headquarters," said the statement, posted on an extremist Web site.

The victims were all members of the Army's 82d Airborne Division, a spokesman for the Fort Bragg, N.C.-based unit said. It was the highest number of casualties for the division since the war began, Maj. Tom Earnhardt said.

"We are recovering, supporting the families during this time of loss, praying for them, and continuing our mission," said Lt. Col. Michael Donnelly, the U.S. military spokesman in northern Iraq. "The enemy brings nothing to benefit the people - nothing."

In its Web posting yesterday, the Islamic State of Iraq, an insurgent umbrella group that includes al-Qaeda in Iraq, put the number of Americans killed at 30.

"Almighty God has guided the soldiers of the Islamic State of Iraq to new methods of explosions," it said without elaborating. The message appeared on a Web site that frequently posts communications from extremists, but its authenticity could not be independently confirmed.

According to a senior Pentagon official, Monday's attack involved suicide bombers in two large dump trucks. One of the trucks got very close to the Sadah patrol base building, and the other was farther away, the official said, adding that at least some of the casualties may have been caused by the collapse of two walls.

It was the single deadliest attack on ground forces since Dec. 1, 2005, when 10 Marines were killed by a bomb inside an abandoned flour mill near Fallujah. Twelve soldiers died when a Black Hawk helicopter crashed in Diyala on Jan. 20. The military said the helicopter might have been shot down but the investigation is continuing.

The use of a suicide bomber in a direct assault against U.S. forces was unusual. Enemy fighters, seeking to avoid U.S. firepower, have often used hit-and-run ambushes, roadside bombs or mortars on U.S. troops.

U.S. troops are facing increasing danger as they step up their presence in outposts and police stations in Baghdad and areas surrounding the city, as part of the security crackdown to which President Bush has committed an extra 30,000 troops.

Sunni militants are believed to have withdrawn to surrounding areas such as Diyala where they have safe haven. The U.S. command also deployed an extra 700 troops to the province last month.

In telephone interviews, residents of the Ameen area south of Baqubah yesterday described what they believed was the same attack that killed the nine soldiers.

The residents, who spoke on condition of anonymity out of fear for their safety, said gunmen first fired on American snipers at a U.S. base housed in an old primary school. They said a suicide car bomb then rammed a checkpoint at the school's entrance, breaking through blast walls and other fortifications. The first explosion left a path for a second suicide vehicle, a truck, to approach the building, the witnesses said.

Several U.S. soldiers were caught beneath the building as it collapsed in the explosion, the residents said.

The Rising Tolls

Deaths in the last two days raised to 85 the number of U.S. service members who have died in Iraq in April, making it the deadliest month for U.S. troops since December, when 112 died.

Eighty-three Iraqis were

killed or found dead across Iraq yesterday.

Gunmen disguised as Iraqi soldiers killed six Iraqis

and burned five homes yesterday. South of Baghdad, seven members of a family were shot to death in their beds at dawn by gunmen, police said.

Near Ramadi, capital of Anbar province, a suicide truck bomb exploded at a police checkpoint, killing 15 people, police said.

And in Baghdad, two bombs went off outside the Iranian Embassy yesterday for the second consecutive day, injuring six civilians.

- Associated PressEndText